RTSP is the IETF-standardized protocol for controlling streaming media servers.
RTSP and SIP share a number of common functions. For example, both establish sessions and use SDP to describe sessions. They are also syntactically similar, as both are HTTP-like textual protocols.
Thus, suggestions are made on occasion to add RTSP functionality to SIP, e.g., to allow SIP to start, stop, pause and position streams.
Generally, these ideas have not made much progress both for practical and technical reasons. Both SIP and RTSP are now widely deployed, so that making significant changes to either would incur large costs and create confusion in the marketplace.
Technically, there are a number of differences that would make adding RTSP functionality to SIP somewhat challenging, without increasing the complexity of media streaming applications. For example, RTSP URIs are hierarchical and based on a file model, while SIP URIs are email-like. RTSP has one-directional media, while SIP usually initiates bidirectional sessions. RTSP has the notion of aggregrate control, where multiple streams are controlled by one control session.
RTSP and SIP share a number of common functions. For example, both establish sessions and use SDP to describe sessions. They are also syntactically similar, as both are HTTP-like textual protocols.
Thus, suggestions are made on occasion to add RTSP functionality to SIP, e.g., to allow SIP to start, stop, pause and position streams.
Generally, these ideas have not made much progress both for practical and technical reasons. Both SIP and RTSP are now widely deployed, so that making significant changes to either would incur large costs and create confusion in the marketplace.
Technically, there are a number of differences that would make adding RTSP functionality to SIP somewhat challenging, without increasing the complexity of media streaming applications. For example, RTSP URIs are hierarchical and based on a file model, while SIP URIs are email-like. RTSP has one-directional media, while SIP usually initiates bidirectional sessions. RTSP has the notion of aggregrate control, where multiple streams are controlled by one control session.